Ammoxidation of a mixture of ketones to acetonitrile and hcn

ABSTRACT

A process increasing the yield of both HCN and acetonitrile produced during the manufacture of acrylonitrile comprising introducing a hydrocarbon selected from the group consisting of propylene and propane, a crude ketone and/or a mixture of at least two ketones, ammonia and air, into a reaction zone containing an ammoxidation catalyst, reacting the hydrocarbon, the ketone, ammonia and oxygen over said catalyst at an elevated temperature to produce acrylonitrile, hydrogen cyanide and acetonitrile, and recovering the acrylonitrile, hydrogen cyanide and acetonitrile from the reactor.

BACKGROUND OF THE INVENTION

[0001] The present invention is directed to a novel process for theammoxidation of a mixture of ketones to a mixture of nitriles. Inparticular, the present invention is directed to increasing the yield ofco-product hydrogen cyanide and acetonitrile produced during theammoxidation of propylene to acrylonitrile.

[0002] There are patents which address the issue of the injection ofacetone into a fluid bed reactor to produce acetonitrile. In addition,these references further disclose that the acetone may be introducedinto a fluid bed reactor to increase the co-product acetonitrile whilemanufacturing acrylonitrile. In particular, Japanese Patent Application2[1990]-38,333 is directed to improving acetonitrile yields by injectingacetone and/or ethyl alcohol into ammoxidation reactor containingammoxidation catalyst. The process disclosed in the Japanese PatentApplication includes simultaneously injecting the acetone and/or ethylalcohol into the ammoxidation reactor while manufacturing acrylonitrile.

[0003] The present invention is directed to a process which increasesthe yield of both main co-products (i.e. HCN and acetonitrile) duringthe manufacture of acrylonitrile while (1) saving on the raw materialcosts associated with the increase in co-product yields and (2)achieving the same or better conversion and selectivity to the desiredco-products.

SUMMARY OF THE INVENTION

[0004] It is an object of the present invention to provide a process forthe ammoxidation of a mixture of ketones and/or a crude ketone tohydrogen cyanide and acetonitrile.

[0005] It is another object of the present invention to provide aprocess for substantially increasing the yields of co-product hydrogencyanide and acetonitrile produced during the manufacture ofacrylonitrile from propylene.

[0006] It is a further object of the present invention to provide aprocess for the conversion of a mixture of ketones (e.g. acetone andmethyl isobutyl ketone (MIBK)) into hydrogen cyanide and acetonitrileduring the manufacture of acrylonitrile without substantially affectingthe yield of the acrylonitrile.

[0007] Additional objects and advantages and novel features of theinvention will be set forth in part in the description which follows,and in part will become apparent to those skilled in the art uponexamination of the following, or may be learned by the practice of theinvention. The objects and advantages of the invention may be realizedand attained by means of the instrumentalities and combinationsparticularly pointed out in the appended claims.

[0008] To achieve the foregoing objects in accordance with the purposeof the present invention as broadly described herein, the method of thepresent invention comprises introducing a hydrocarbon selected from thegroup consisting of propylene and propane, a mixture of ketones (e.g.acetone and MIBK), ammonia and oxygen-containing gas into reaction zone(e.g fluid bed reactor)to react in the presence of a catalyst (e.g.fluid bed catalyst) to produce a reactor effluent comprisingacrylonitrile, hydrogen cyanide and acetonitrile, passing the reactoreffluent containing acrylonitrile, hydrogen cyanide and acetonitrileinto a quench column to cool the reactor effluent, and recovering theacrylonitrile, acetonitrile and hydrogen cyanide from the quench column.

[0009] In another aspect of the present invention, the process comprisesintroducing a mixture of ketones (e.g. acetone and MIBK) and/or a crudeketone, ammonia and oxygen-containing gas into reaction zone (e.g. fluidbed reactor) to react in the presence of a catalyst (e.g. fluid bedcatalyst) to produce a reactor effluent comprising hydrogen cyanide andacetonitrile, passing the reactor effluent containing the hydrogencyanide and acetonitrile into a quench column to cool the reactoreffluent, and recovering the acetonitrile and hydrogen cyanide from thequench column. In the practice of this aspect of the present inventionthe ammoxidation conditions used in the manufacture of acrylonitrile asdisclosed in U.S. Pat. No. 3,911,089 herein incorporated by referencemay be utilized.

[0010] For purposes of the present invention, the mixture of ketones isintended to include mixtures of commercially available ketones such asacetone, MIBK, methyl ethyl ketone etc. in either their purified,substantially purified, or crude form. In addition, commerciallyavailable crude ketones may be used by itself in the practice of thepresent invention. For purposes of this application the term “crudeketone” shall mean a mixture of at least two ketones and a diluent (e.g.crude acetone shall comprises primarily acetone containing other ketonesas impurities and water as a diluent).

[0011] In the practice of the present invention, it is envisioned thatany ammoxidation catalyst can be utilized to achieve the desiredresults. Typical ammoxidation catalysts can be generalized by thefollowing two formulae:

A_(a)B_(b)C_(c)D_(d)Mo₁₂O_(x) where

[0012] A=Li, Na, K, Cs, Tl and combinations thereof, preferably Cs and K

[0013] B=Ni, Co, Mn, Mg, Ca and combinations thereof, preferably Ni, Coand Mg

[0014] C=Fe, Cr, Ce, Cu, V, Sb, W, Sn, Ga, Ge, In, P and combinationsthereof, preferably Fe, Cr and Ce

[0015] D=Bi and/or Te, preferably Bi

[0016] a=0.1-4.0, preferably 0.1 to 0.5, especially preferred being 0.1to 0.2

[0017] b=0.1-10.0, preferably 5 to 9, especially preferred being 6 to 8,and

[0018] c,d=0.1-10.0, preferably 0.5 to 4, especially preferred being 0.5to 3;

and A_(a)B_(b)Sb₁₂O_(x) where

[0019] A=Fe, Cr, Ce, V, U, Sn, Ti, Nb and combinations thereof,preferably Fe, V, Sn and Ti

[0020] B=Mo, W, Co, Cu, Te, Bi, Zn, B, Ni, Ca, Ta and combinationsthereof, preferably Mo and Cu

[0021] a=0.1-16, preferably 2 to 12, especially preferred being 4 to 10

[0022] b=0.0-12, preferably 1 to 10, especially preferred being 2 to 6,and

[0023] the value of x depends on the oxidation state of the elementsused.

[0024] The catalyst can be used either unsupported, or be supported withsilica, alumina, titania, zirconia and the like; however, silica is thepreferred support. Typically, catalysts envisioned as suitable in thepractice of the present invention are disclosed in U.S. Pat. Nos.3,642,930; 4,485,079; 3,911,089, 4,873,215; 5,134,105 and 5,093,299,herein incorporated by reference.

[0025] Reference will now be made in detail to the present preferredembodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention is primarily directed to the utilization ofa mixture of at least two ketones such as acetone and methyl isobutylketone as a source for the production of useful nitrile co-products(hydrogen cyanide and acetonitrile) produced during the manufacture ofacrylonitrile. However, the process of the present invention is alsoapplicable to the manufacture of on purpose acetonitrile and hydrogencyanide by the direct ammoxidation of a mixture of C₁ to C₄ ketoneand/or a crude ketone, ammonia and oxygen in a reaction zone in thepresence of an ammoxidation catalyst. In addition, crude ketone (asdefined above), by itself, may be utilized in the practice of thepresent invention thereby further reducing the cost of the raw materialssuitable for the production of viable co-products.

[0027] The practice of the process of the present invention during themanufacture of acrylonitrile increases the yield of both HCN andacetonitrile during the manufacture of acrylonitrile. The practice ofthis aspect of the present invention comprises introducing a hydrocarbonselected from the group consisting of propylene and propane, a crudeketone, ammonia and air, into a reaction zone containing an ammoxidationcatalyst, reacting the hydrocarbon, ketone, ammonia and oxygen over saidcatalyst at an elevated temperature to produce acrylonitrile, hydrogencyanide and acetonitrile, and recovering the acrylonitrile, hydrogencyanide and acetonitrile from the reactor.

[0028] In another embodiment of this aspect of the present invention,the process comprises introducing a hydrocarbon selected from the groupconsisting of propylene and propane, a mixture of at least two C₁ to C₄ketones, ammonia and air, into a reaction zone containing anammoxidation catalyst, reacting the hydrocarbon, ketones, ammonia andoxygen over said catalyst at an elevated temperature to produceacrylonitrile, hydrogen cyanide and acetonitrile, and recovering theacrylonitrile, hydrogen cyanide and acetonitrile from the reactor.

[0029] In the preferred embodiment of this aspect of the presentinvention, it is necessary that the reactor conditions be adjusted toobtain the increased yield in acetonitrile and hydrogen cyanide obtainedby utilizing the mixture of ketones and/or crude ketone. In the practiceof the present invention, the ammoxidation reaction conditions should bewithin the following parameters: Crude ketone is between 1 and 50% ofpropylene or propane rate on a total carbon basis. The temperature ofthe reaction is between 410° to 460° C., preferably 405° to 440° C.Typically, the pressure is maintained at between 1 to 5 atmospheres with1 to 3 atmospheres being preferred.

[0030] In a further preferred embodiment of this aspect of the presentinvention the crude ketone mixture comprises a mixture containingacetone, MIBK and water.

[0031] In a still further preferred embodiment of this aspect of thepresent invention the process is performed in a fluid bed reactor.

[0032] In another preferred embodiment of this aspect of the presentinvention the mixture of ketones comprises crude ketone in combinationwith at least one substantially pure C₁ to C₄ ketone.

[0033] In still another preferred embodiment of this aspect of thepresent invention, the ketone is separately introduced into the reactorzone.

[0034] In a still further preferred embodiment of this aspect of thepresent invention, the mixture of ketones and/or crude ketone isseparately introduced into the fluid bed reactor, preferably at alocation above the point where the hydrocarbon is fed into the reactor,especially preferred being a location in the upper portion of thereactor.

[0035] The following examples are set forth below for illustrativepurposes and are not considered as limiting to the practice of thepresent invention. The catalyst utilized in all of the examples was apromoted BiFeMoO_(x) known for its suitability in the ammoxidation ofpropylene to acrylonitrile. Five, 10 and 15% of the propylene feed (interms of total carbon) was replaced with a ketone to give the resultsset forth below in Table I. In each of the following examples thereactor temperature was 430° C., the pressure was 9.5 psig and the feedratio of propylene +alcohol/ammonia/air was 1/1.2/9.3. The wwh was 0.06(grams of hydrocarbon/grams of catalyst-hour) TABLE I Example % Acetoneas % AN % Aceto % HCN No. C Fed Yield Yield Yield 1 (comp.)  0 78.6 2.06.7 2  5 75.5 3.1 7.5 3 10 72.3 4.1 8.4 4 15 68.3 5.2 9.6

[0036] As a further example of the value of using crude ketones, 10% byweight water was blended with the acetone above and this was co-fed tothe same propylene ammoxidation reactor. The results are shown below inTable II and indicate that water dilution has no deleterious effect onperformance. TABLE II Example % Blend as % AN % Aceto % HCN No. C FedYield Yield Yield 5 (comp.)  0 78.9 2.0 6.6 6  5 75.3 3.2 7.8 7 10 71.74.2 8.7 8 15 67.5 5.3 9.6

[0037] In general, all ketones can be ammoxidized to a mixture ofnitrites. The preferred ketones include C₁ to C₄ ketones. The followingexample illustrates the use of a C4 ketone in the form of methyl ethylketone (MEK). TABLE III Example % MEK as % AN % Aceto % HCN No. C FedYield Yield Yield 9 (comp.) 0 79.2 2.1 6.9 10 2.5 77.6 3.2 7.0 11 5 75.54.2 7.4

[0038] The following examples are illustrative of the practice of thepresent invention for direct ammoxidation of ketones to acetonitrile andHCN. The feed ratio for the ketone/ammonia/air used in Example 12 and 13were 1/1.7/13.1 and 1/2/15.1 respectively. The temperature of thereaction was 413° C. for Example 12 and 41 1° C. for Example 13. Thereactor pressure was 10 psig for both examples and the wwh was 0.133 and0.149 for Examples 12 and 13, respectively. Table IV below sets forththe results for Examples 12 and 13. TABLE IV Example % Aceto % HCN No.ketone % Conversion Yield Yield 12 acetone 98.9 28.0 27.8 13 methylethyl 99.9 46.0 16.5 ketone

[0039] While the examples are illustrative of the practice of thepresent invention, they are not intended to limit applicants' inventionto that illustrated and obviously many modifications and variations maybe utilized in light of the above teaching. It is intended that thescope of applicants' invention be defined by the claims appended hereto.

What we claim as our invention is:
 1. A process for increasing the yield of co-product HCN and acetonitrile produced during the manufacture of acrylonitrile comprising introducing a hydrocarbon selected from the group consisting of propylene and propane, a crude ketone, ammonia and air into a reaction zone containing an ammoxidation catalyst, reacting the hydrocarbon, crude ketone, ammonia and oxygen over said catalyst at an elevated temperature to produce acrylonitrile, hydrogen cyanide and acetonitrile, and recovering the acrylonitrile, hydrogen cyanide and acetonitrile from the reactor.
 2. The process of claim 1 wherein the crude ketone comprises a mixture of at least two C₁ to C₄ ketones and water.
 3. The process of claim 1 wherein the feed ratio of hydrocarbon: ketone ranges from 1:0.01 to 1:0.5, on a total carbon basis.
 4. The process of claim 3 wherein the temperature ranges from 410° to 460° C.
 5. The process of claim 4 wherein the temperature ranges from 430° to 450° C.
 6. The process of claim 4 wherein the pressure ranges from 1 to 5 atmospheres.
 7. The process of claim 5 wherein the pressure ranges from 1 to 5 atmospheres.
 7. The process of claim 1 wherein the crude ketone comprises crude acetone.
 8. The process of claim 1 wherein the ammoxidation catalyst is characterized by the following formula: A_(a)B_(b)C_(c)D_(d)Mo₁₂O_(x) where A=Li, Na, K, Cs, Ti and combinations thereof B=Ni, Co, Mn, Mg, Ca and combinations thereof C=Fe, Cr, Ce, Cu, V, Sb, W, Sn, Ga, Ge, In, P and combinations thereof D=Bi and/or Te, preferably Bi a=0.1-4.0, preferably 0.1 to 0.5 b=0.1-10.0, preferably 5 to 9, and c,d=0.1-10.0, preferably 0.5 to
 4. 9. The process of claim 1 wherein the ammoxidation catalyst is characterized by the following formula: A_(a)B_(b)Sb₁₂O_(x) where A=Fe, Cr, Ce, V, U, Sn, Ti, Nb and combinations thereof B=Mo, W, Co, Cu, Te, Bi, Zn, B, Ni, Ca, Ta and combinations thereof a=0.1-16, preferably 2 to 12 b=0.0-12, preferably 1 to 10, and the value of x depends on the oxidation state of the elements used.
 10. A process for increasing the yield of co-product HCN and acetonitrile produced during the manufacture of acrylonitrile comprising introducing a hydrocarbon selected from the group consisting of propylene and propane, a mixture of at least two ketones, ammonia and air into a reaction zone containing an ammoxidation catalyst, reacting the hydrocarbon, ketones, ammonia and oxygen over said catalyst at an elevated temperature to produce acrylonitrile, hydrogen cyanide and acetonitrile, and recovering the acrylonitrile, hydrogen cyanide and acetonitrile from the reactor.
 11. The process of claim 10 wherein the mixture of ketone comprises at least two C₁ to C₄ ketones.
 12. The process of claim 11 wherein the mixture of ketones comprises acetone and methyl isobutyl ketone.
 13. The process of claim 12 wherein the mixture of ketones comprises a crude ketone and at least one substantially pure C₁ to C₄ ketone.
 14. The process of claim 13 wherein the temperature ranges from 410° to 460° C.
 15. The process of claim 14 wherein the temperature ranges from 430° to 450° C.
 16. The process of claim 14 wherein the pressure ranges from 1 to 5 atmospheres.
 17. The process of claim 15 wherein the pressure ranges from 1 to 5 atmospheres.
 18. The process of claim 10 wherein the ammoxidation catalyst is characterized by the following formula: A_(a)B_(b)C_(c)D_(d)Mo₁₂O_(x) where A=Li, Na, K, Cs, Ti and combinations thereof B=Ni, Co, Mn, Mg, Ca and combinations thereof C=Fe, Cr, Ce, Cu, V, Sb, W, Sn, Ga, Ge, In, P and combinations thereof D=Bi and/or Te, preferably Bi a=0.1-4.0, preferably 0.1 to 0.5 b=0.1-10.0, preferably 5 to 9, and c,d=0.1-10.0, preferably 0.5 to
 4. 19. The process of claim 10 wherein the ammoxidation catalyst is characterized by the following formula: A_(a)B_(b)Sb₁₂O_(x) where A=Fe, Cr, Ce, V, U, Sn, Ti, Nb and combinations thereof B=Mo, W, Co, Cu, Te, Bi, Zn, B, Ni, Ca, Ta and combinations thereof a=0.1-16, preferably 2 to 12 b=0.0-12, preferably 1 to 10, and the value of x depends on the oxidation state of the elements used.
 20. A process for the ammoxidation of a mixture of C₁ to C₄ ketones to produce HCN and acetonitrile comprising introducing the mixture of ketones, ammonia and air into a reaction zone containing an ammoxidation catalyst, reacting the ketones, ammonia and oxygen over said catalyst at an elevated temperature to produce hydrogen cyanide and acetonitrile, and recovering the hydrogen cyanide and acetonitrile from the reactor zone.
 21. A process for the ammoxidation of a crude ketone to produce HCN and acetonitrile comprising introducing the crude ketone, ammonia and air into a reaction zone containing an ammoxidation catalyst, reacting the ketone, ammonia and oxygen over said catalyst at an elevated temperature to produce hydrogen cyanide and acetonitrile, and recovering the hydrogen cyanide and acetonitrile from the reactor zone. 